Raven,

That's good feedback. Please let us know your test results.

Ken Lambert will be making my mufflers. In the "What a Deal" thread on this engine Lambert's mufflers generated significant increases over the stock set up.

In another thread a 16 to 1 ratio was quoted as being sufficient to minimize noise without restricting power. Using that ratio the muffler for a 25cc engine would need to be 400cc. I won't be able to test that theory until I get it on a stand and devise a way to change the main muffler canister (some kind of header / chamber design like a Pitts).